:root {
  --radius: 18px;
  --radius-sm: 14px;
  --max: 1180px;
}

html[data-resolved-theme="light"] {
  --bg: #f4f7fb;
  --main-bg: #ffffff;
  --panel: #ffffff;
  --panel-2: #f9f9f9;
  --line: rgba(15, 23, 42, 0.08);
  --text: #18202a;
  --muted: #5f6b7a;

  --brand: #0f4c81;
  --brand-2: #0c416e;
  --brand-line: rgba(255, 255, 255, 0.16);
  --brand-text: #ffffff;
  --brand-muted: rgba(255, 255, 255, 0.82);

  --shadow: 0 18px 50px rgba(15, 23, 42, 0.08);
}

html[data-resolved-theme="dark"] {
  --bg: #08111b;
  --main-bg: #0d1722;
  --panel: #122031;
  --panel-2: #152538;
  --line: rgba(255, 255, 255, 0.08);
  --text: #eef4fb;
  --muted: #b4c1cf;

  --brand: #0d4a7d;
  --brand-2: #093b64;
  --brand-line: rgba(255, 255, 255, 0.12);
  --brand-text: #ffffff;
  --brand-muted: rgba(255, 255, 255, 0.82);

  --shadow: 0 20px 60px rgba(0, 0, 0, 0.28);
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

html,
body {
  margin: 0;
  padding: 0;
}

body {
  font-family: Arial, Helvetica, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.65;
}

img {
  display: block;
  max-width: 100%;
}

a {
  color: inherit;
  text-decoration: none;
}

button {
  font: inherit;
}

svg {
  display: block;
}

.container {
  width: min(var(--max), calc(100% - 32px));
  margin: 0 auto;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 1000;
  background: linear-gradient(180deg, var(--brand), var(--brand-2));
  color: var(--brand-text);
  border-bottom: 1px solid var(--brand-line);
  transform: translateY(0);
  transition: transform 0.28s ease, box-shadow 0.28s ease;
}

.site-header.is-hidden {
  transform: translateY(calc(-100% - 8px));
}

.site-header.is-scrolled {
  box-shadow: 0 14px 40px rgba(0, 0, 0, 0.18);
}

.header-brand-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
  padding: 16px 0 14px;
}

.header-nav-row {
  padding: 12px 0 14px;
  border-top: 1px solid var(--brand-line);
}

.site-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 18px;
}

.site-nav a,
.mobile-nav a,
.footer-nav a {
  font-size: 0.95rem;
  color: var(--brand-text);
  opacity: 0.95;
  transition: opacity 0.2s ease;
}

.site-nav a:hover,
.mobile-nav a:hover,
.footer-nav a:hover {
  opacity: 1;
}

.site-nav a[aria-current="page"],
.mobile-nav a[aria-current="page"],
.footer-nav a[aria-current="page"] {
  font-weight: 700;
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 14px;
  margin-left: auto;
  flex: 0 0 auto;
}

.icon-btn,
.menu-toggle {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 26px;
  height: 26px;
  padding: 0;
  border: 0;
  background: transparent;
  color: var(--brand-text);
  cursor: pointer;
  appearance: none;
  -webkit-appearance: none;
  box-shadow: none;
}

.icon-btn:hover,
.menu-toggle:hover {
  opacity: 0.88;
}

.icon-btn:focus-visible,
.menu-toggle:focus-visible {
  outline: 2px solid rgba(255, 255, 255, 0.78);
  outline-offset: 4px;
  border-radius: 6px;
}

/* 普通图标：只描边，不填充 */
.icon-btn svg,
.menu-toggle svg,
.theme-icon-light,
.theme-icon-dark {
  width: 22px;
  height: 22px;
  fill: none;
  stroke: currentColor;
  stroke-width: 1.9;
  stroke-linecap: round;
  stroke-linejoin: round;
}

/* system 图标单独控制 */
.theme-cycle-btn {
  position: relative;
}

.theme-icon {
  display: none;
}

.theme-icon-system {
  width: 22px;
  height: 22px;
}

.theme-icon-system .system-ring {
  fill: none;
  stroke: currentColor;
  stroke-width: 1.8;
}

.theme-icon-system .system-half {
  fill: currentColor;
  stroke: none;
}

html[data-theme="system"] .theme-icon-system,
html[data-theme="light"] .theme-icon-light,
html[data-theme="dark"] .theme-icon-dark {
  display: block;
}

.menu-toggle {
  display: none;
}

.menu-toggle .icon-close {
  display: none;
}

.menu-toggle.is-open .icon-menu {
  display: none;
}

.menu-toggle.is-open .icon-close {
  display: block;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 16px;
  min-width: 0;
  flex: 1 1 auto;
}

.brand img {
  width: 58px;
  height: 58px;
  border-radius: 16px;
  background: #ffffff;
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.14);
  flex: 0 0 auto;
}

.brand-copy {
  display: flex;
  flex-direction: column;
  gap: 4px;
  min-width: 0;
}

.eyebrow {
  display: block;
  font-size: 0.82rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--brand-muted);
}

.brand-copy strong {
  font-size: 1.55rem;
  line-height: 1.15;
  color: var(--brand-text);
}

.mobile-menu {
  display: none;
  padding: 0 0 18px;
}

.mobile-menu.is-open {
  display: block;
}

.mobile-nav {
  display: grid;
  gap: 10px;
  padding-top: 12px;
  border-top: 1px solid var(--brand-line);
}

.main {
  background: var(--main-bg);
}

.hero {
  padding: 42px 0 18px;
  background: var(--main-bg);
}

.hero-wrap {
  display: block;
}

.hero-card {
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 36px 32px;
  box-shadow: var(--shadow);
}

.section-kicker,
.card-kicker {
  display: inline-block;
  font-size: 0.8rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: #0f4c81;
}

html[data-resolved-theme="dark"] .section-kicker,
html[data-resolved-theme="dark"] .card-kicker {
  color: #8cc3ff;
}

.hero-card h1 {
  margin: 12px 0 14px;
  font-size: clamp(2rem, 4vw, 3.4rem);
  line-height: 1.08;
}

.hero-card p {
  margin: 0;
  max-width: 760px;
  color: var(--muted);
  font-size: 1.06rem;
}

.section {
  padding: 18px 0 64px;
  background: var(--main-bg);
}

.grid-two {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 22px;
}

.card {
  background: var(--panel-2);
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  padding: 26px 24px;
}

.card h2 {
  margin: 12px 0 10px;
  font-size: 1.3rem;
}

.card p {
  margin: 0;
  color: var(--muted);
}

.site-footer {
  background: linear-gradient(180deg, var(--brand), var(--brand-2));
  color: var(--brand-text);
  border-top: 1px solid var(--brand-line);
}

.footer-wrap {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 24px;
  padding: 28px 0 34px;
}

.site-footer strong {
  display: block;
  margin-bottom: 8px;
  font-size: 1.06rem;
}

.site-footer p {
  margin: 0;
  max-width: 620px;
  color: var(--brand-muted);
}

.footer-nav {
  display: flex;
  flex-wrap: wrap;
  justify-content: flex-end;
  gap: 14px 18px;
  max-width: 420px;
}

@media (max-width: 900px) {
  .site-nav {
    gap: 14px;
  }

  .grid-two {
    grid-template-columns: 1fr;
  }

  .footer-wrap {
    flex-direction: column;
  }

  .footer-nav {
    justify-content: flex-start;
  }
}

@media (max-width: 760px) {
  .container {
    width: min(var(--max), calc(100% - 24px));
  }

  .header-brand-row {
    padding: 12px 0;
  }

  .header-nav-row {
    display: none;
  }

  .menu-toggle {
    display: inline-flex;
  }

  .icon-btn,
  .menu-toggle {
    width: 24px;
    height: 24px;
  }

  .icon-btn svg,
  .menu-toggle svg,
  .theme-icon-light,
  .theme-icon-dark,
  .theme-icon-system {
    width: 22px;
    height: 22px;
  }

  .brand img {
    width: 58px;
    height: 58px;
    border-radius: 14px;
  }

  .brand-copy strong {
    font-size: 1.2rem;
  }

  .eyebrow {
    font-size: 0.72rem;
  }

  .header-actions {
    justify-content: flex-end;
  }

  .hero {
    padding-top: 26px;
  }

  .hero-card {
    padding: 28px 20px;
  }

  .hero-card h1 {
    font-size: 2rem;
  }
}